Some of these drugs are also used in patients who have had heart failure or a recent heart attack. One-hundred-and-four drugs were cleared of the measure Monday while the remaining 115 carcinogen-containing pills remain off the market, following component analyses.

Drugs that contain valsartan are used in treating high blood pressure and help to prevent heart attacks and stroke. The circular has also directed that all healthcare practitioners and doctors should not prescribe or dispense the affected products and also advises patients to not discontinue use of the medicine unless they consult with the doctor to prescribe other alternatives registered with the Ministry.

N-Nitrosodimethylamine, or NDMA, is an organic chemical often produced as a byproduct of industrial processes and present in low levels in food that is smoked, cured or cooked.

Other medicines containing valsartan are not affected. The company says that "no other Sandoz or Novartis products, even those that may contain valsartan, are affected by the recall".

Health Canada announced that the drugs were coming from China, from Zhejiang Huahai Pharmaceuticals.

Health Canada describes NDMA as "a potential human carcinogen, which means that it could cause cancer with long-term exposure". Of 484,682 kilograms of Valsartan imported over the last three years, only 13,770 kilograms, or 2.8 percent contain ingredients from China.

On Saturday, the Health Insurance Review & Assessment Service revised its Drug Utilization Review, a computerized pharmaceutical review system that oversees prescriptions, to display an on-screen warning when doctors try to prescribe a banned drug on their computers.

The Ministry has affirmed that it is always in close coordination and communication with the FDA and the European and Australian Medicines agencies to get any updates and take any necessary actions as soon as possible to protect the health of patients and people in the country.